Development of dynamic impact cone for assessing induced partial saturation (IPS) as liquefaction mitigation technique

Fritz R P Nababan,D Roosmini,B Sugeng,I.K Hadihardaja,K Pribadi

doi:10.1051/matecconf/201814707006

Abstract

Liquefaction of saturated loose sands during an earthquake has been a great concern for practicing earthquake engineer because of its damaging effects. Current liquefaction mitigation techniques used in practice are expensive. A new innovative mitigation technique which is cost effective was proposed by Yegian et al. [1] called “Induced Partial Saturation” (IPS). This method involves in generating gas bubbles within the pores of fully-saturated sand and transformed it to partially-saturated sand. This paper described the development of a dynamic impact cone to assess the effect of this IPS treatment on saturated loose sand specimens. This dynamic impact cone consists of a cone, rod, ruggedized pressure transducer, string pot, and DAQ. The cone which has pressure transducer incorporated at its tip was driven into fully and partially (treated) saturated sand specimens prepared in the laboratory. The excess pore pressures and penetrations depth per impact of the two specimens were compared. The tests results such as the excess pore pressure and the penetration indicate that the impact penetration on the fully-saturated specimens liquefied sand, but could not liquefy the partially-saturated sand. Therefore the concept and development of this dynamic impact cone has promising future applications.

Highlights

Liquefaction of saturated loose sands during earthquake event poses a great concern for practicing geotechnical earthquake engineer because tremendous damage it can cause
One promising new mitigation technique which is innovative, practical, and cost effective was proposed by Yegian et al [1] called “Induced Partial Saturation” (IPS)
It is expected that if the same cone is driven into the same specimen after being treated with IPS, the presence of gas bubbles in the pores will considerably reduce the generation of excess pore pressure

Summary

Introduction

Liquefaction of saturated loose sands during earthquake event poses a great concern for practicing geotechnical earthquake engineer because tremendous damage it can cause. One promising new mitigation technique which is innovative, practical, and cost effective was proposed by Yegian et al [1] called “Induced Partial Saturation” (IPS). This technique involves generating small amount of minute gas bubbles within the pores of initially fully-saturated sand, reducing the saturation degree and at the same time increasing the compressibility of the soil pores. Small scale laboratory testing has shown the benefit of IPS as described in Yegian et al [1] and EsellerBayat et al [2],[3]. The detail of the developed cone is described as well as the typical results of the test

Dynamic Impact Cone

Prototype Cone

Developed Dynamic Impact Cone

Heavy Duty Pressure Transducer

Specimen Preparation and Test Set Up

Conclusions and Recommendations